Sound absorption of micro-perforated thin plates in a duct

Hyun-Sil Kim; Bong-Ki Kim; Sang-Ryul Kim; Yun-Ho Seo; Pyung-Sik Ma

doi:10.7776/ASK.2017.36.5.305

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2017 Vol.36, Issue 5 Preview Page Next Page

Sound absorption of micro-perforated thin plates in a duct 덕트내 미세천공 박판의 흡음

30 September 2017. pp. 305-313

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Abstract

In this paper, sound absorption of thin elastic plates installed in a rigid duct is discussed using an analytic method. The number of plates can be one or two, and each plate might have micro-perforation. Vibration of the plates and sound pressure fields inside the duct and air cavity are expressed in terms of an infinite series of modal functions. Under the plane wave assumption, a low frequency approximation is derived by including the first few plate modes. It is found that the sound absorption coefficient of the plates without micro-perforation shows sharp peaks at resonance frequencies, and due to the interaction between the plates and air cavity, the resonance frequencies move as the cavity depth changes. For the case of micro-perforated plates, it is found that the sound absorption is mainly affected by the perforation ratio. When the perforation ratio is order of few percent, the sound absorption is almost independent of plate vibration.

Keywords

Sound absorption

Micro perforated plate

Duct

Elastic plate

본 논문은 강체 덕트 내에 고정된 얇은 탄성 판의 흡음을 해석적으로 구하는 방법을 다루었다. 판의 개수는 1개 또는 2개이며 각각의 판은 미세천공(micro-perforation)을 포함할 수도 있다. 판의 진동과 덕트 내부 음장을 모드 함수의 무한 급수의 합으로 전개하였다. 평면파 가정하에서 저주파수 대역의 근사식을 판의 처음 몇 개의 모드만 고려하여 유도하였다. 미세천공이 없는 판의 흡음율은 공진주파수에서 피크를 보이는데 공진주파수는 판과 캐비티의 상호작용으로 인하여 캐비티 간격이 변하면 공진주파수도 변함을 알 수 있었다. 미세천공판의 경우 천공율이 흡음율에 가장 큰 영향을 미치는 요소임을 확인하였는데, 천공율이 몇 퍼센트에 이르면, 흡음율은 거의 판의 진동에 영향을 받지 않는다.

키워드

흡음

미세천공판

덕트

탄성판

References

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 36
No :5
Pages :305-313
Received Date : 2017-08-07
Accepted Date : 2017-09-28
DOI :https://doi.org/10.7776/ASK.2017.36.5.305

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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